The carbapenem antibiotics constitute a diverse group of .beta.-lactam antibiotics characterised by potent anti-bacterial and .beta.-lactamase-resistant activity. More than forty different carbapenems are known, most of which are produced by the actinomycetes, particularly Streptomyces spp (Ratcliffe and Albers-Schonberg, 1982; Brown 1984; Williamson 1986; all cited in Baiton et al 1992).
Carbapenems have been isolated from the Gram-negative bacterium Serratia marcescens and Erwinia carotovora by Parker et al. (1982) and in Azospirillum spp UK 1521 by Kintaka et al. (1985); all cited in Bainton et al 1992.
Bainton et al (1992) have recently shown that carbapenem biosynthesis is regulated by the regulatory factor N-(3-oxohexanoyl)-L-homoserine lactone (known as HSL or OHHL). This compound was previously only known for its role in auto-induction of bioluminescence in the marine bacterium Vibrio fischeri. OHHL is also structurally related to the A- and I-factors which are known to regulate production of antibiotics in some Streptomyces species.